So you want to first remove all the stuff in the corner (basically remove the strainer (i believe that is what it is called) you will route your usb/serial cable over to this area
Next you will follow the wires that come from the DME to the firewall, when you get to the firewall you will find a grommet
when you start to feed it into the grommet you will see it come out by the fuse box in the glove box

Hope this helps you out, I was a little behind and could not get the picture of the grommet, kinda a PITA to get a picture of